Mix brake fluid with bleach. What will happen?
Content
Composition of components and reagents
Brake fluid contains polyglycols - polymeric forms of polyhydric alcohols (ethylene glycol and propylene glycol), boric acid polyesters and modifiers. Chlorine includes hypochlorite, hydroxide and calcium chloride. The main reagent in the brake fluid is polyethylene glycol, and in bleach - hypochlorite. There is also a liquid form of chlorine-containing household products, in which sodium hypochlorite serves as an oxidizing agent.
Process description
If you mix bleach and brake fluid, you can see an intense reaction with a copious release of gas. The interaction does not occur immediately, but after 30-45 seconds. After the formation of a geyser, the gaseous products ignite, which often ends in an explosion.
It is not recommended to conduct the experiment at home. For the procedure, protective equipment should be used, and the reaction should be carried out in a fume hood or in an open space at a safe distance.
Reaction mechanism
In the experiment, freshly prepared bleach is used. Instead of bleach, you can use sodium hypochlorite, which contains up to 95% active chlorine. At the beginning, the hypochlorite salt decomposes with the formation of atomic chlorine:
NaOCl → NaO+ + CI—
The resulting chloride ion bombards the molecule of ethylene glycol (polyethylene glycol), which leads to the destabilization of the polymer structure and redistribution of the electron density. As a result, the monomer, formaldehyde, is separated from the polymer chain. The ethylene glycol molecule is converted into an electrophilic radical, which reacts with another chloride ion. At the next stage, acetaldehyde is separated from the polymer, and ultimately the simplest alkene, ethylene, remains. The general breakdown scheme is as follows:
Polyethylene glycol ⇒ Formaldehyde; Acetaldehyde; Ethylene
The destructive destruction of ethylene glycol under the action of chlorine is accompanied by the release of heat. However, ethylene and formaldehyde are flammable gases. Thus, as a result of heating the reaction mixture, the gaseous products ignite. If the reaction rate is too fast, an explosion occurs due to the spontaneous expansion of the gas-liquid mixture.
Why doesn't the reaction take place?
Often when mixing brake fluid and bleach, nothing is observed. This happens for the following reasons:
- Used old household bleach
When stored outdoors, calcium hypochlorite slowly decomposes to calcium carbonate and calcium chloride. The content of active chlorine is reduced to 5%.
- Low temperature
For the reaction to proceed, it is necessary to heat the brake fluid to a temperature of 30-40 ° C
- Not enough time has passed
A radical chain reaction occurs with a gradual increase in speed. It will take about 1 minute for visual changes to appear.
Now you know what will happen if bleach is mixed with brake fluid and how the interaction occurs.
